Question

查询1：

SELECT DISTINCT sysnam,COUNT(*) AS High FROM tablename
WHERE Label00002 = '1.High' AND Item_grade = 'NON-COMPLIANT'
GROUP BY sysnam

输出：

SYSNAME，高

         A,12

         B,13

查询2：

SELECT DISTINCT sysnam,count(*) AS Medium FROM tablename
WHERE Label00002 = '2.Medium' AND Item_grade = 'NON-COMPLIANT'
GROUP BY sysnam

输出：SYSNAME，Medium

         A,10

         B,11

如何将上述查询合并为一个，并希望看到输出如下

输出：

SYSNAME，高，中

       A,12,10

       B,13,11

Answer 1

使用条件聚合：

select sysnam, 
       sum(case when Label00002 = '1.High' then 1 else 0 end) as high,
       sum(case when Label00002 = '2.Medium' then 1 else 0 end) as medium
from tablename
where Item_grade = 'NON-COMPLIANT' 
group by sysnam;

注意：当您拥有select distinct时，使用group by几乎绝对不正确。

Answer 2

您可以在基于相同的sysnam

的subselect上使用连接

select distinct t1.sysnam,count(t1.*) as High, t2.Medium 
from tablename t1
left join (
    select distinct sysnam,count(*) as Medium from tablename
    where Label00002 = '2.Medium' and Item_grade = 'NON-COMPLIANT'
    group by sysnam
  ) t2 on t2.sysnam = t1.sysnam
where t1.Label00002 = '1.High' 
and t1.Item_grade = 'NON-COMPLIANT'
group by sysnam

Answer 3

将查询放入两个CTE并加入结果

delete_admin()

需要帮助将两个sql查询合并为1

3 个答案: